How to use it
- Enter the stake and oddsThe stake in naira and the decimal odds on offer.
- Enter your chanceYour own estimate, in percent, that the bet wins. Be strict with yourself here.
- CompareA positive expected value means the odds pay more than your estimate says they should.
The formula
EV = chance × profit if it wins minus (1 minus chance) × stake. As a percentage of stake: EV% = chance × odds minus 1. The break-even chance is 1 ÷ odds.
Worked example
You can back a team at 2.50 with ₦1,000. You think it wins 45% of the time. EV = 0.45 × ₦1,500 minus 0.55 × ₦1,000 = ₦675 minus ₦550 = ₦125, or 12.5% of the stake. The break-even chance at 2.50 is 40%, so your estimate sits 5 points above it.
| Your chance | EV on ₦1,000 at 2.50 |
|---|---|
| 35% | minus ₦125 |
| 40% | ₦0 |
| 45% | ₦125 |
| 50% | ₦250 |
Expected value is only as good as your chance estimate. If you rate every pick 5 points too high, every bet will look like value. Track your results before you trust your numbers.
Expected value FAQ
Does positive EV mean the bet will win?
No. It means that over many similar bets you would be ahead on average. Any single bet can still lose.
Where do I get a chance estimate?
From your own model or records, or from the fair odds of a sharp market with the margin removed. The margin calculator gives fair chances.
How much should I stake on a value bet?
The Kelly calculator turns your edge into a stake size. Most punters use a fraction of it.
Can a bonus make a bet positive EV?
Yes, a free bet or a price boost can tip a bet over break-even. Our free bet calculator shows how much a free bet is worth.